The menopausal transition may represent a critical developmental time period during which subtle cognitive deficits may be revealed. The pattern of cognitive deficits which may be seen during this time period may be useful for identifying individuals who are at risk for developing dementia later in life. The overall goal of this study is to determine if cognitive deficits described by many perimenopausal women can be objectively measured. We will also examine the affective and hormonal milieu in which these deficits may exist and how these factors are related to reported cognitive changes. The specific aims of this pilot study are to determine if objective cognitive deficits are present in perimenopausal women and to determine if putative estrogen effects on cognitive performance are mediated by estrogen effects on mood state. 30 early- perimenopausal and 30 late-perimenopausal women between the ages of 40 and 60 will be evaluated at 6- month intervals for one year. Comprehensive neuropsychological (NP) assessment, psychological assessment, psychosocial and health assessment, and reproductive hormone levels will be obtained at each visit. Early and late perimenopausal women will be compared with respect to NP test performance and mood and anxiety symptoms using t-tests. Regression/correlation analyses will be performed to investigate the associations between hormones, NP test performance, and mood and anxiety symptoms. To determine if the relationship between estrogen and cognition is mediated by estrogen's relationship with mood, we will use structural equation modeling (SEM). The findings of this study may influence current treatment of perimenopausal women, who are often faced with significant psychosocial stressors and age-related physiologic changes during this time period. An understanding of the nature of cognitive declines, and whether they are transient or signify a risk for neurodegenerative disease, would either alleviate women's concerns about subjective cognitive lapses or allow for early identification and treatment. An understanding of the possible mechanisms of such declines would assist care providers in their treatment and referral of women with cognitive and psychological symptoms. [unreadable] [unreadable] [unreadable]